Method of making catheter

ABSTRACT

A hand-actuated retention catheter 5 is disclosed. The retention catheter includes a tube 12, an overcoat layer 14 encircling the tube 12 and a cavity 16 interposed between the tube 12 and the overcoat layer 14. The cavity 16 encircles the tube and includes a bulbous balloon portion 24 and an enlarged fluid reservoir portion 22 interconnected and separated by a catheter sleeve portion 26 which has a narrowed outside diameter. The expandable balloon portion 24 can be expanded by compressing the fluid reservoir portion 22. Methods of making the hand-actuated retention catheter and methods of using the same are also disclosed.

CROSS-REFERENCE TO OTHER APPLICATIONS

This is a Continuation of application Ser. No. 08/469,646, filed Jun. 6,1995, abandoned, which is a divisional of U.S. patent application Ser.No. 08/284,381, filed Aug. 2, 1994, now U.S. Pat. No. 5,593,718 which adivisional application of U.S. patent application Ser. No. 07/827,936,filed Jan. 29, 1992, now U.S. Pat. No. 5,360,402 which is acontinuation-in-part application of U.S. patent application Ser. No.07/809,281, filed Dec. 13, 1991, now U.S. Pat. No. 5,261,896 which is acontinuation-in-part of U.S. patent application Ser. No. 07/489,462,filed Mar. 6, 1990, now abandoned which is a continuation-in-partapplication of U.S. patent application Ser. No. 07/487,422, filed Mar.1, 1990, now U.S. Pat. No. 5,098,379 which is a continuation-in-partapplication of U.S. patent application Ser. No. 07/462,832, filed Jan.10, 1990, now U.S. Pat. No. 5,137,671 the disclosures of which are eachincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to balloon catheters which are eitherimplantable or insertable into a human body, particularly hand-actuatedballoon catheters. These devices have expandable retention balloonswhich can be expanded once the device is positioned within the body,thereby providing a mechanism for preventing the removal of the catheteronce it is so positioned. The present invention also relates to methodsfor making the same, products made by these methods, and methods ofusing the hand-actuated balloon catheter.

BACKGROUND OF THE INVENTION

Catheters are tube like devices which are inserted into a portion of aperson's body in order to transport fluids, such as liquids, gases, andsometimes semisolids, in or out of that particular portion of the body.For instances, urinary catheters are used to transport urine collectedin the bladder out of the body via the urinary tract. Other types ofcatheters such as gastronomy devices, transport fluids into and out ofvarious segments of the gastrointestinal system, primarily the stomach.

In order to provide a means of retaining the catheter within the body,inflatable bag catheters were introduced many years ago. Subsequently,Foley (U.S. Pat. No. 3,409,016) taught an elongated catheter having asecondary lumen for inflating a retention balloon at a distal end of thecatheter once the distal end is positioned within the body. Suchcatheters are now generally referred to as "Foley" catheters out ofrespect for the contribution made by Dr. Foley.

Improvements on Dr. Foley's contribution to the catheter art continue tofind their way into the market place today. In spite of the manypractical uses for these devices today, they do have limitations, a fewof which are discussed below. First, they are difficult for untrainedindividuals to use, especially relatively untrained nursing homeattendants and/or patient's who may wish to care for their own needs.Second, because the fluid to expand the balloon is delivered from anexternal source, it is possible to burst the balloon by injecting toomuch fluid. It will be appreciated that this creates a safety concern.Third, it is possible that the secondary lumen which communicates withthe cavity of the expandable balloon may become clogged during use ofthe catheter, thereby creating a problem when it becomes time to deflatethe expandable balloon and remove the catheter. Fourth, the outersurface of the catheter leading to the balloon can irritate internalsurfaces of the body with which it comes into contact, thereby creatinginflamed areas which can be painful to the patient and may be moresusceptible to bacterial infection. Fifth, the conduit portion of thecatheter immediately adjacent to the expandable balloon does not fullyengage or conform to the internal surfaces of the body approximate theexpandable balloon. In the case of a urinary catheter, this oftenenables urinary fluids from the bladder to pass through the sphincter atthe proximal end of the urinary passageway, thereby allowing urinaryfluids to leak out of the bladder into the urinary passageway, therebycreating a risk of infection for the catheterized patient. Sixth, thecost of manufacturing traditional Foley catheters has been influenced bythe need to use a significant amount of hand labor to make the devices.It will be appreciated that efforts to reduce the amount of hand laborin the manufacture of such devices may reduce the cost of such devicesso that they are more competitive in the market place.

It will be appreciated, therefore, that there is a need for a retentioncatheter, as well as methods for making and using the same, which willaddress these and other problems associated with prior art devices andmethods. The present invention provides advantages over the prior artcatheters, over the prior art methods for manufacturing and using thesame, and also offers other advantages over the prior art and solvesother problems associated therewith.

SUMMARY OF THE INVENTION

Accordingly, a hand-actuated retention catheter is provided by thepresent invention. The hand-actuated retention catheter comprises a tubehaving outer and inner surfaces, the inner surface defining an innerlumen, an overcoat layer encircling the tube, the overcoat layer havinginterior and exterior surfaces, a cavity interposed between the tube andovercoat layer, encircling the tube and being defined by portions of theouter surface of the tube and portions of the interior surface of theovercoat layer, and a fluid within the cavity. The overcoat layerincludes an "expandable balloon" or expandable balloon section and a"squeeze bulb" or fluid reservoir section interconnected by a"constricting conduit" or catheter sleeve section. The overcoat layer isjoined to the outer surface of the tube at distal and proximal ends ofthe cavity. The cavity includes an expandable balloon portion and afluid reservoir portion interconnected by a catheter sleeve portion. Thecatheter sleeve section of the overcoat layer defines a narrowing in thecavity through which fluid passing from the fluid reservoir portion tothe expandable balloon portion thereof must pass and preferably includesrestriction means for restricting the passage of fluid from theexpandable balloon portion to the fluid reservoir portion via thecatheter sleeve portion of the cavity, wherein a sufficient amount ofthe fluid can pass from the fluid reservoir portion, through thecatheter sleeve portion, and into the expandable balloon portion whenthe fluid reservoir portion is compressed, so that the expandableballoon portion of the cavity is enlarged and the outer surface of theovercoat layer proximate the balloon section thereof is also enlarged.Although the catheter sleeve portion of the cavity, and thecorresponding catheter sleeve section of the overcoat layer, can havevirtually any practical length, for the commercial embodiments presentlyenvisioned, they will preferably have lengths of at least about 0.5inches, more preferably at least about 1 inch, even more preferably atleast about 1.5 inches, and most preferably at least about 2 inches.

It is an object of the present invention to provide a retention catheterincluding a retention balloon and a hand-actuated mechanism forexpanding the retention balloon. This will enable relatively untrainedpersonnel to insert and remove such catheters and may enable patient'sto insert and remove them as well. It is also object of the presentinvention to provide a retention catheter which provides a safetyadvantage over presently available balloon catheters. The presentcatheter includes a certain amount of fluid which can be repositioned inthe expandable balloon portion of the cavity so as to expand the balloonsection of the overcoat layer. Because the expansion of the balloonsection is actuated by compressing the fluid reservoir section of theovercoat layer and the fluid reservoir portion of the cavity, andbecause that portion of the cavity includes only a limited andpredetermined amount of fluid, it is less likely that a user will overinflate the balloon causing it to rupture within the body, when insertedtherein.

It is also noted that the catheter sleeve portion of the cavity providesa larger conduit for fluid passing into the balloon portion of thecavity than is ordinarily available in prior art balloon catheters or"Foley" catheters. It will also be appreciated that it will be much moredifficult to block this larger conduit, and, consequently, most unlikelythat the user will experience any difficulty deflating the balloon whenit is time to remove the catheter. Furthermore, if the expandableballoon section of the overcoat layer proves to be difficult to deflatewhen the catheter is to be removed, it will be easy to obtain access tothe fluid reservoir portion of the cavity by puncturing the fluidreservoir section of the overcoat layer which will remain generallyoutside of the internal passageways of the patient in which the catheteris inserted. This will allow the user to insure that the expandableballoon section can be deflated by manipulating the fluid in the fluidreservoir portion of the cavity.

It is also an object of the present invention to provide a cathetersleeve section of the overcoat layer which provides a constrictionbetween the fluid reservoir portion and the expandable balloon portionof the cavity. The catheter sleeve section is preferably a compliantmembrane which can move relatively independently of the tube so as toreduce the tendency for slight movements of the catheter tube toirritate the inner walls of the internal passageway in which thecatheter is inserted. Furthermore, the catheter sleeve section, becauseof its relative independence of movement in respect to the cathetertube, can, in combination with the cushioning effect of the fluid filledcatheter sleeve portion of the cavity adjacent thereto, generally complywith the shape of internal passageways through which it passes, therebyreducing the likelihood of any leakage of fluids through suchpassageways. This is especially true for preferred embodiments which areused as urinary catheters wherein the expandable balloon section isexpanded within a person's bladder for retention therein. In such asituation, the adjacent catheter sleeve section, in combination withcushioning activity of the fluid in the adjacent catheter sleeve portionof the cavity, will tend to conform to the shape of the urinarypassageway adjacent to the sphincter of the bladder so that leakagethrough the sphincter and into and through the urinary passageway can beminimized. It will be appreciated that limiting the leakage of urine inthis way will greatly reduce the risk of bacterial colonization andinfection within the urinary passageway and the bladder itself, byeliminating the opportunity for pools of urine to collect and stagnatewithin the urinary passageway.

It is a further object of the present invention to provide methods ofmaking the inventive catheters which provide significant costefficiencies relative to the prior art methods of producing retentioncatheters. The present device is preferably fabricated primarily ofsilicone rubber and can be manufactured using an automated systememploying a series of coating steps. Although any means of applying therespective coatings may be used, the preferred method employs a seriesof dipping steps which enable the manufacturer to shape the initialcavity and the overcoat layer, thereby providing the overcoat layer withcertain properties which are believed to be desirable in order toprovide the retention catheter of the present invention.

These and various other advantages and features of novelty whichcharacterize the present invention are pointed out with particularity inthe claims annexed hereto and forming a part hereof. However, for abetter understanding of the present invention, its advantages and otherobjects obtained by its use, reference should be made to the drawings,which form a further part hereof, and to the accompanying descriptivematerial, in which there is illustrated and described preferredembodiments of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, in which like and primed, reference numerals indicatecorresponding parts throughout the several views,

FIG. 1 is a transverse schematic view of a hand-actuated retentioncatheter in accordance with the present invention in partialcross-section;

FIG. 2 is a cross-sectional view of the retention catheter shown in FIG.1 as seen generally from the line 2--2 thereof;

FIG. 3 is a transverse schematic view of a portion of the catheter, asshown in FIG. 1, showing a portion of the fluid in the fluid reservoirportion of the cavity passing through the catheter sleeve portion of thecavity and into the expandable balloon portion of the cavity in responseto force exerted upon the fluid reservoir section of the overcoat layer;

FIG. 4 is a cross-sectional view of the retention catheter shown in FIG.3 as seen generally from the line 4--4 thereof;

FIG. 5 is a view of the retention catheter similar to that of FIG. 3,except that the expandable balloon is in a fully expanded position;

FIG. 6 is a view of the retention catheter similar to that shown inFIGS. 3 and 5, except that a restriction disc for restricting thepassage of fluid from the expandable balloon portion of the cavity tothe fluid reservoir portion of the cavity via the catheter sleeveportion thereof has been manipulated to allow fluid to flow from theexpandable balloon portion to the fluid reservoir portion under thepressure of the resilient expandable balloon section of the overcoatlayer;

FIG. 7 is a cross-sectional view of the retention catheter shown in FIG.6, as seen generally from the line 7--7 thereof;

FIG. 8 is a transverse schematic sectional view showing a partialcross-section of a catheter similar to the retention catheter shown inFIG. 1 when inserted in a urethral tract of a patient, but prior toexpansion of the expandable balloon;

FIG. 9 is a view similar to that shown in FIG. 8, except that the"squeeze bulb" of the retention catheter has been compressed and theexpandable balloon has been fully expanded;

FIG. 10 is a transverse schematic view of a tube in partialcross-section which is used to make the retention catheter shown in FIG.1;

FIG. 11 is a transverse schematic view of the tube shown in FIG. 10following the addition of a tip at the distal end thereof;

FIG. 12 is a partial cross-sectional view of the tube shown in FIG. 11when secured upon one of a plurality of support rods on a moveablepallet, and following the addition of a coating of a removablebond-preventing agent to a portion of the outer surface of the tube;

FIG. 13 is a view similar to that shown in FIG. 12, but after theaddition of an additional thickness of the removable bond-preventingagent to the outer surface of the tube;

FIG. 14 is a transverse schematic view of the tube shown in FIGS. 11-13,but showing only the removable bond-preventing agent in cross-sectionand only after a portion thereof has been removed from the outer surfaceof the tube;

FIG. 15 is a transverse schematic view similar to that shown in FIG. 14,but after an additional coating of removable bond-preventing agent hasbeen added to the outer surface of the tube;

FIG. 16 is a transverse schematic view similar to that shown in FIG. 15,but after a further thickness of removable bond-preventing agent isadded to the outer surface of the tube;

FIG. 17 is a transverse schematic view similar to that shown in FIG. 16,but after a portion of the removable bond-preventing agent on the outersurface of the tube is removed;

FIGS. 18A and 18B are transverse schematic views similar to that shownin FIG. 17, but showing an overcoat layer on the outer surface of thetube;

FIG. 19 is a schematic illustration of apparatus used to automate theproduction of retention catheters in accordance with the presentinvention similar to that shown in FIG. 1;

FIGS. 20A, 20B and 20C are flow charts disclosing steps of methods ofmanufacturing retention catheters in accordance with the presentinvention;

FIG. 21 is a schematic representation of the automated controls for theapparatus shown in FIG. 19, used to automate the production of retentioncatheters made in accordance with the present invention;

FIG. 22 is a transverse schematic view of an alternate hand-actuatedretention catheter in accordance with the present invention in partialcross-section similar to the view shown in FIG. 1;

FIG. 23 is a cross-sectional view of the alternate retention cathetershown in FIG. 22 as seen generally from the line 23--23 thereof;

FIG. 24 is a cross-sectional view of the retention catheter shown inFIG. 22 as seen generally from the line 24--24 thereof;

FIG. 25 is a transverse schematic view of another alternatehand-actuated retention catheter in accordance with the presentinvention in partial cross-section similar to the view shown in FIG. 1;

FIG. 26 is a cross-sectional view of the alternate retention cathetershown in FIG. 25 as seen generally from the line 26--26 thereof;

FIG. 27 is a transverse schematic view of a portion of the alternateretention catheter shown in FIG. 25, showing the balloon section in anexpanded state and the fluid reservoir section in a compressed state;

FIG. 28 is a transverse schematic view of yet another alternatehand-actuated retention catheter in accordance with the presentinvention in partial cross-section similar to the view in FIG. 1; and

FIG. 29 is a cross-sectional view of the alternate retention cathetershown in FIG. 28 as seen generally from the line 29--29 thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, and specifically to FIGS. 1-9, thepresent invention provides a hand-actuated retention catheter 5. Theretention catheter has an inner lumen 8 defined by an inner surface 10of a tube 12. The retention catheter 5 further includes an overcoatlayer 14 which encircles the tube 12. Interposed between the tube 12 andthe overcoat layer 14 is a cavity 16. The cavity 16 contains a fluid 18.The overcoat layer 14 is joined to an outer surface 20 of the tube 12both above and below the cavity 16 along the length of the tube 12. Thecavity 16 includes a fluid reservoir portion 22 and a expandable balloonportion 24, interconnected by a catheter sleeve portion 26 such thatfluid 18 can pass between the fluid reservoir portion 22 and theexpandable balloon portion 24 via the catheter sleeve portion 26. Theovercoat layer 14 includes a fluid reservoir section 30 or "squeezebulb", an expandable balloon section 32 or "expandable balloon", whichare interconnected by a catheter sleeve section 34 or "constrictingconduit".

The catheter 5 further includes an eyelet 40 at a distal end 42 of thecatheter 5 which communicates with the lumen 8. Preferred embodimentsinclude a plug 44 for closing the lumen 8 at the proximal end 46 of thecatheter 5 to limit the unrestrained passage of bodily fluids (notshown) through the lumen 8 and out of the catheter 5. A resilientrestriction disc 50 or "washer" encircles the retention catheter 5proximate the catheter sleeve section 34 of the overcoat layer anddistal to the fluid reservoir portion 22 of the cavity 16. The resilientrestriction disc 50 provides a mechanism for restricting the passage offluid 18 between the expandable balloon portion 24 and the fluidreservoir portion 22 of the cavity 16 via the catheter sleeve portion 26thereof. It will be appreciated that any other restriction device ormethod for restricting the flow of fluid through a cylindricalpassageway may also be used in place of the resilient restriction disc50 of the present invention. In preferred embodiments, the resilientrestriction disc 50 resembles a washer having an inner perimeter 52which has an inner diameter in its resting state, which is preferably,just slightly less than an outside diameter of the tube 12. Theresilient restriction disc 50 will be expanded somewhat about its innerperimeter when it is in its normal engaged state, as shown in FIGS. 1and 2 when placed on the catheter 5 proximate the constricting conduit34. Because of its resilient nature, the disc 50 will press theconstricting conduit 34 of the overcoat layer 14 up against the outersurface 20 of the tube 12, so that fluid 18 cannot pass through thecatheter sleeve portion 26 of the cavity 16 unless forced to do so.Preferably, the force necessary to allow fluid 18 to pass can be appliedby squeezing the squeeze bulb 30 before the expandable balloon 32 isexpanded, but not by the force exerted by the expandable balloon 32 byitself once it is expanded.

In FIGS. 1 and 2, the restriction disc 50 is shown in its normal engagedstate, wherein the disc 50 encircles the catheter sleeve section 34,thereby restricting the passage of fluid 18 through the catheter sleeveportion 26 of the cavity 16. In order to expand the expandable balloonportion 24 of the cavity 16 and the expandable balloon section 32 of theovercoat layer 14, the squeeze bulb can be compressed by hand to force aportion of the fluid 18 in the fluid reservoir portion 22 of the cavity16 through the catheter sleeve portion 26 and into the expandableballoon portion 24. By compressing the fluid reservoir portion 22 of thecavity 16, sufficient force can be placed on a narrowing of theconstricting conduit 34 proximate the disc 50 to enlarge the resilientinner perimeter 52 of the restriction disc 50 enough to permit fluid 18to pass through the catheter sleeve portion 26, thereby allowing theballoon portion 24 to be expanded as shown in FIGS. 3 and 4. When fullyexpanded in this way, the balloon 32 will provide a bulbous enlargementat the distal end 42 of the catheter 5 which is generally effective toprevent the removal of the retention catheter 5 from an internalpassageway 68 in which the retention catheter 5 is positioned (see alsoFIGS. 8 and 9). Once the expandable balloon portion 24 of the cavity 16and the expandable balloon section 32 of the overcoat layer 34 have beenfully expanded, as shown in FIGS. 5 and 9, the balloon 32 can be"deflated" or returned generally to its normal, unexpanded state,generally shown in FIGS. 1 and 8 by grasping opposite sides of theresilient restriction disc 50 and pulling them in opposite directions sothat fluid 18 can pass through the catheter sleeve portion 26 of thecavity 16 as shown in FIGS. 6 and 7. By grasping the disc 50 on oppositesides and pulling in opposite directions, the resilient disc 50 can bedeformed so as to pull the inner perimeter 52 away from the tube 12 onopposite sides of the tube 12 so that the constricting conduit 34 is notfully engaged with the entire circumference of the outer surface 20 ofthe tube 12, and the fluid 18, driven by the force of the resilient,expandable balloon 32, flows into the fluid reservoir portion 22 of thecavity 16. Because the expandable balloon section 32 of the overcoatlayer 14 is made of a resilient polymeric material, preferably siliconrubber, the expandable balloon portion 24 of the cavity 16 will becompressed by the force exerted by the expandable balloon section 32when the resilient restriction disc 50 is manipulated to permit fluid 18to pass through the catheter sleeve portion 26 of the cavity 16. In thisway, the expandable balloon section 32 can generally return to itsnormal, unexpanded state and fluid 18 can generally return to the fluidreservoir portion 22. Once the expandable balloon section 32 is returnedits normal unexpanded state, as shown generally in FIG. 8, the retentioncatheter 5 can then be easily removed from the internal passageway 68 inwhich it resides.

Referring now also to FIGS. 10-19, certain preferred methods of makingthe preferred hand-actuated retention catheter 5 (shown in FIG. 1) aredescribed. These catheters 5 are made of silicone rubber, although itwill be appreciated that other suitable polymeric materials may be usedto make the present invention.

Referring now initially to FIG. 10, a resilient, polymeric tube 12,preferably a silicone rubber tube 12, is provided. Although such a tube12 can be provided by extruding a ribbon of polymeric tubing and cuttingthe tubing into desired lengths, in the Applicants' initialmanufacturing efforts, commonly available medical grade silicone rubbertubing has been purchased and then cut into desired lengths.

Referring now also to FIG. 11, once cut into desired lengths, apolymeric tip 56 is secured, preferably molded, to the distal end 60 ofthe tube 12 to close off the lumen 8 at the distal end 60 and therebycreate an intermediate tube 3. The tip 56 is preferably added byinserting the tube 12 in a mold (not shown) or a tip-forming device (notshown), in which a desired amount of uncured silicone rubber is injectedto form the tip once the tube 12 is inserted therein. The uncuredsilicone rubber will preferably be a self-leveling RTV (room temperaturevulcanizing) silicone rubber such as Dow Corning 734 Self Leveling RTVSilicone rubber from Dow Chemical, Midland, MI. Presently, theApplicants use an intermediate tube 3 made in this way. It isenvisioned, however, that a preferred process may be developed whereinthe entire intermediate tube 3, including the tube 12 and a tip similarto tip 56 will be made by dipping a mandrel (not shown) in a suitablepolymeric material in a manner which is effective to create theintermediate tube 3. Any other convenient methods for securing a tip tothe tube 12 may also be used.

Referring now also to FIGS. 12-21, the intermediate tube 3 is secured toa support rod 62 on a moveable pallet 64. FIG. 19 provides a schematicrepresentation of a preferred mechanized catheter production line 81which is virtually fully automated. The mechanized production line 81includes one or more pallets 64 having a plurality of support rods 62.The moveable pallet 64 is attached to a transport mechanism 82 which canmove the pallet to a position over one of a plurality of dip tanks84,86,88,90,92,94. Each of the respective dip tanks will contain a fluidin which intermediate catheters 3 secured upon respective support rods62 are immersed when the respective dip tank is raised. Movement of thepallet 64 is controlled by an output from a computer control mechanism83, illustrated schematically in FIG. 21, which are directed to thetransport mechanism 82. Each of the respective dip tanks84,86,88,90,92,94 are raised and lowered by associated lift mechanisms.The lift mechanisms are also controlled by outputs from the computercontrol mechanism 83. Each of the lift mechanisms includes a speedcontrol capable of modulating the rate at which the respective dip tankis raised and lowered so that the speed at which the respectiveintermediate tubes 3 are immersed into and withdrawn from the respectivefluid within the respective dip tank can be varied. The computer controlmechanism 83 also receives inputs from depth sensors within each of therespective dip tanks. The depth sensors, preferably ultrasonic depthsensors, are capable of providing an input to the computer controlmechanism 83 which enables the computer control mechanism to determinewhen the intermediate tubes 3 are immersed to a desired depth in therespective dip tank. Timers are also provided for each of the respectivedip tanks in order to provide inputs to the computer control mechanism83 so that the computer control mechanism 83 can determine when adesired period of time has elapsed. A computer program is provided whichmoves the pallet along the mechanized production line 81 and raises andlowers the respective dip tanks at predetermined times, at predeterminedrates of speed, and to predetermined locations and/or heights to enablethe mechanized production line 81 to produce a plurality of completedintermediate catheters 4 from the intermediate tubes 3 secured to therespective support rods 62. In alternate embodiments, the mechanizedproduction line 81 may have a series of pallets (not shown) which aremoved along an alternate transport mechanism (not shown) in series.

The moveable pallet 64 will preferably have a plurality of support rods62 to accommodate a plurality of intermediate tubes 3. In alternateembodiments, a tube 12 can be secured to the support rod 64, andsubsequently dipped in polymeric material in a manner sufficient to adda polymeric tip 56 so as to created an intermediate tube 3.

The intermediate tube 3 is then coated with a removable bond-preventingagent 66, preferably petroleum jelly or petrolatum, which forms a firstcoating 75 covering first, second, third, and fourth portions 20a, 20b,20c and 20d of the outer coating 20 of the intermediate tube 3. This ispreferably accomplished by dipping the intermediate tube into a bath ofheated petroleum jelly or petrolatum. Additional removablebond-preventing agent 66 is then coated onto the first coating 75 toform a second coating 76. This second coating 76 is preferably muchthicker than the first coating 75. Portions of the second coating 76 arethen stripped off of the second, third, and fourth portions 20b, 20c,and 20d of the outer surface 20, and a third coating 77 of removablebond-preventing agent 66 is placed on the second, third, and fourthportions 20b, 20c, and 20d of the outer surface 20. A fourth coating 78is then added proximate the third and fourth portions 20c and 20d of theouter coating 20 over the third coating 77. The third and fourthcoatings 77 and 78 of removable bond-preventing agent 66 coating thefourth portion 20d of the outer surface 20 are then removed, and theouter surface 20 of the intermediate tube 3 and the remaining portionsof the second, third, and fourth coatings 76, 77, and 78 of removablebond-preventing agent 66 covering the first, second, and third portions20a, 20b, and 20c of the outer surface 20, respectively, are coated witha suitable polymeric material, preferably silicone rubber, which adheresto the outer surface 20 of the intermediate tube 3 above the firstportion 20a thereof and below the third portion 20c, and creates anovercoat layer 14 having an exterior surface 36.

Although the present hand-actuated retention catheter 5 can beconstructed of any suitable, medically acceptable, polymeric material,medical grade silicone rubber is preferred. It will be appreciated thatsuch a silicone rubber polymeric must be fully cured prior to sale oruse. In the preferred methods of making the present hand-actuatedretention catheter 5, the intermediate tube 3 is dipped into a bath ofuncured silicone rubber to form the overcoat layer 14. Following thisstep, the overcoat layer 14 is air-dried and subsequently cured to forma completed intermediate catheter 4, such as that shown in FIG. 18. Theovercoat layer 14 of the completed intermediate catheter 4 is then curedand removed from the pallet 64. The completed intermediate catheters 4are then, preferably, further cured and then soaked in a bath of hotmineral oil for several hours. In the preferred embodiment, the mineraloil will diffuse through the overcoat layer 14 and into the petrolatumin the cavity 16, and the petrolatum will diffuse out of the cavity intothe hot mineral oil. The remaining fluid 18 in the cavity 16 will be amineral oil/petrolatum fluid having a significantly lower viscosity thanpetrolatum at room temperature. A different fluid such as water, sterilesaline, glycerin, polyethylene glycol, and the like, or mixtures thereofmay also be substituted for the mineral oil/petrolatum fluid inalternate embodiments by removing most of the latter fluid, and theninserting the former by any appropriate means.

An eyelet 40 is then punched through the overcoat layer 14 and the tube12 proximate the fourth portion 20d of the outer surface 20, in order toprovide an opening which communicates with the lumen 8 from the outsideof the intermediate catheter 4. An end piece 80 is then secured to theproximal end 61 of the intermediate catheter 4 to form a completedhand-actuated retention catheter 5, and the completed retention catheter5 is tested.

During the testing of the completed retention catheter 5, a removablecylindrical support device 98 is secured around the catheter sleevesection 34 of the overcoat layer 14 adjacent to the expandable balloonsection 32, as shown in FIG. 18B, to minimize any potential expansion ofthe catheter sleeve section 34. In this way, when the fluid reservoirsection 30 is compressed, and the expandable balloon section 32 isexpanded for the first time, the catheter sleeve section 34 will only beallowed to expand minimally, if at all, because the removablecylindrical support device 98 prevents, or at least minimizes, expansionof the catheter sleeve section 34. It has been observed that, once theexpandable balloon section 32 of the overcoat layer 14 has beeninitially expanded in this way, it is easier to expand the expandableballoon 32 in subsequent attempts. On the other hand, since the cathetersleeve section 34 of the overcoat layer has not been stretched to thesame degree, it will be more resistant to expansion or stretching thanthe expandable balloon 32 in subsequent attempts. Therefore, the step ofinitially expanding the balloon section 32, helps to create a retentioncatheter 5 which has a readily expandable balloon section 32, as opposedto the catheter sleeve section 34 which does not expand as readily uponcompression of the fluid reservoir section 30.

Following the testing of the expandable balloon 32, the expandablerestriction disc 50 is secured onto the retention catheter 5 by slippingthe distal end 42 of the catheter 5 through the disc 50 until the disc50 encircles the catheter 5 proximate the catheter sleeve section 34 ofthe overcoat layer 14 just distal to the squeeze bulb 30.

Referring now to FIGS. 6, 7, 8 and 9, during use, the hand-actuatedretention catheter 5 of the present invention is inserted into a urinarypassageway 68 of a patient 70 until the expandable balloon section 32 ispositioned within the patient's bladder 72. In preferred embodiments,the catheter sleeve section 34 of the overcoat layer will be about 0.5to about 3.5, preferably about 1.5 to about 2.5, more preferably about 2inches long for insertion into the urinary passageway 68 of a femalepatient. When the length of the preferred catheter sleeve section 34 isthe same as that of such a female patient's urinary passageway, thedistal end 42 and the catheter sleeve section 34 of the retentioncatheter 5 are inserted until the expandable restriction disc 50 and thesqueeze bulb limit further insertion into the urinary passageway 68. Theexpandable balloon 32 is then expanded by grasping the squeeze bulb 30and squeezing it to compress the fluid reservoir portion 22 of thecavity 16, thereby providing enough force to drive the fluid 18 throughthe catheter sleeve portion 26 of the cavity 16 and into the expandableballoon portion 24 thereof. The expandable balloon 32 will then expand,and the inner perimeter 52 of the expandable restriction disc 50 willsubsequently force the catheter sleeve section 34 of the overcoat layer14 against the outer surface 20 of the tube 12 about an entirecircumference thereof, so that the fluid 18 cannot return to the fluidreservoir portion 30 and the expandable balloon 32 will remain in itsfully expanded state.

When the expandable balloon 32 is in its fully expanded state (as shownin FIG. 9), the retention catheter 5 will be secured within the urinarypassageway 68 because the expandable balloon 32 will be larger than thenormal opening in the urinary passageway 68 proximate the sphincter 58at the distal end of the bladder 72. In order to remove the retentioncatheter 5 from the urinary passageway 68, a user will grasp oppositesides of the expandable restriction disc 50 and pull in oppositedirections, thereby deforming the restriction disc 50 in a mannersimilar to that shown in FIG. 7. If sufficient force is used, the innerperimeter 52 of the restriction disc 50 can be pulled away from theouter surface 20 of the tube 12 on opposite sides thereof, so that fluidcan pass through the catheter sleeve portion 26 of the cavity 16 underpressure created by the resilient overcoat layer 14 which is expandedproximate the expandable balloon 32. The force generated by theexpandable balloon 32 will preferably be sufficient to push sufficientfluid 18 out of the expandable balloon portion 24 of the cavity 16 sothat the expandable balloon 32 generally returns to its normalunexpanded state, similar to that shown in FIG. 1, and the retentioncatheter 5 can be withdrawn from the bladder 72 and the urinarypassageway 68 without difficulty.

If, for some reason, the fluid 18 does not automatically flow back intothe fluid reservoir portion 26 of the cavity 16 when the restrictiondisc 50 is deformed, as described hereinabove, it is possible to removethe restriction disc 50 entirely and even puncture the overcoat layer 14proximate the squeeze bulb 30 to allow the fluid 18 to drain out of thecavity 16. Alternatively, further compression of the squeeze bulb 30 mayurge sufficient additional fluid 18 through the catheter sleeve portion26 of the cavity 16 to dislodge any obstruction therein which mayotherwise prevent the fluid 18 from flowing out of the expandableballoon portion 24 and back into the fluid reservoir portion 22.

The expandable restriction disc 50 of the present invention may be madeof any resilient polymeric material. In preferred embodiments, however,the restriction disc 50 will be made of silicone rubber. The overcoatlayer 14 of the present retention catheter 5 preferably has a thicknessless than the thickness of the tube 12 between its outer surface 20 andits inner surface 10. In preferred embodiments, the thickness of theovercoat layer 14 will be about 0.010 to about 0.030, preferably about0.015 to about 0.025, more preferably about 0.017 to about 0.023, mostpreferably about 0.020 inches (about 0.05 cm). The thickness of the tube12 will be comparable to that of the tube in Applicant's priorapplications incorporated herein by reference. The overcoat layer 14 ispreferably very soft and compliant, and will move relativelyindependently of the tube 12. For instance, when the proximal end 46 ofthe retention catheter 5 is either twisted, pushed, or pulled whilepositioned within the urinary passageway 68 of the patient 70, the tube12 can twist, and move inward and outward in respect to the passageway68 with a significant degree of independence of the overcoat layer 14,which will stretch and twist in response to such movements, butnecessarily be compelled to move relative to its position within theinternal passageway 68 in response to such movements. It will beappreciated that this will reduce the amount of irritation caused by theexterior surface 36 of the retention catheter 5, because this relativeindependence of the respective elements of the catheter will allowstructural portions of the catheter 5 to move independently of theexterior surface 36, which is most likely to be in contact with internalsurfaces of the respective passageways in which the catheter 5 isinserted. It will also be appreciated that the advantages this willafford are analogous to the advantages set forth in U.S. patentapplication Ser. No. 07/487,422, filed Mar. 1, 1990, the disclosure ofwhich is incorporated herein by reference. It will be furtherappreciated that the present invention provides additional advantagesover the catheters disclosed therein, because the catheter sleevesection 34 hereof is secured only to the adjacent sections of theovercoat layer 14 and not to the tube 12. This is believed to provideeven more independence of movement to the tube 12 and the otherstructural portions of the retention catheter 5 which are resilientlyinterconnected with the catheter sleeve section 34.

In the Applicants' use of the preferred methods of the presentinvention, catheter production is almost completely automated. Sets ofcatheters 5 are manufactured simultaneously. The preferred pallet 64 has400 spring steel support rods 62 attached to the pallet in 20 rows ofrods, wherein each of the rods 62 is about 1 inch from each adjacentrod. Tubing (not shown) can be either purchase or made by an extrusionprocess known to those of skill in the art. The tubes 2 are cut tolength, tipped and secured on the pallet 64.

In a preferred embodiment of the present method, 400 of the intermediatetubes 3 are mounted vertically on rigid spring steel support rods 62 ona moveable pallet 64. The pallet 64 is then moved via a transportmechanism 82 (see FIG. 19) over a series of dip tanks 84,86,88,92,94, 96as follows in one of these embodiments:

(A) The pallet 64 is stopped over a first tank 84, which contains aliquid petrolatum mixture at about 125# F. (about 52# C.). The mixtureis the preferred removable bond-preventing agent 66. The mixture willinclude 45% Perfecta™ Petrolatum USP (from Sonneborn Petrolatums,Sonneborn Div., Witco Chemical Corp., New York, N.Y.); 45% Mineral JellyNo. 17 (from Sonneborn Petrolatums); and 10% Parafin (Amoco ESKAR™ wax,Amoco Oil Co., Chicago, Ill.). The tank is raised so as to immerse theintermediate tubes 3 into the petrolatum to such a depth (up to dashedline A shown in FIGS. 12 and 13) that the petrolatum coats the first,second, third and fourth portions 20a, 20b, 20c and 20d of the outersurface 20. The dip tank 84 is then lowered and these portions of theouter surface 20 of the intermediate tubes 3 are coated with a firstcoating 75 of petrolatum. The tubes 3 are allowed to air dry for about30 seconds, and the dip tank is raised again and the tubes 3 areimmersed again to the same depth. This is repeated 48 times until asecond petrolatum coating 76 is completed which is very thick (see FIGS.12 and 13).

(B) The pallet 64 is then automatically advanced and stopped over asecond dip tank 86 which contains hot USP petrolatum heated to about180° F. (about 82# C.).

The second dip tank 86 is raised so as to immerse the intermediate tubes3 into the super-heated petrolatum for 1 minute so that the super-heatedpetrolatum comes up to dashed line B and into contact with the secondpetrolatum coating 76 on the second, third and fourth portions 20b, 20cand 20d of the outer surfaces 20 of the intermediate tubes 3 from theprior dipping step. The second dip tank 35 is then lowered. This dippingstep causes the coating 77 of petrolatum from the prior dipping step tobe largely removed from the second, third and fourth portions 20b, 20cand 20d of the outer surface 20 of the intermediate tubes 3, as shown inFIG. 14. Some residual petrolatum may remain on these portions of theouter surface 20. However, most of the petrolatum is removed from them.

(C) The pallet 64 is then automatically advanced and stopped over athird dip tank 88 containing a liquid petrolatum mixture identical tothat in the first dip tank 84, except that the temperature is about 135°F. (about 57# C.). The third dip tank 88 is then raised so as to immersethe intermediate tubes 3 into the petrolatum mixture to the same depthas they were immersed in the super-heated petrolatum in the second diptank 86. The tank 88 is then lowered, leaving a third coating 77 ofpetrolatum on the second, third and fourth portions 20b, 20c and 20d ofthe outer surface 20, as shown in FIG. 15. The tubes are then immersedtwice again up to the dashed line C and a fourth coating 78 is createdover the third and fourth portions 20c and 20d of the outer surface 20(as shown in FIG. 16) which is roughly 3 times as thick as the thirdcoating 77, but not nearly as thick as the second coating 76.

(D) The pallet 64 is then automatically advanced and stopped over afourth dip tank 90 containing hot USP petrolatum like that in the seconddip tank 86. The fourth dip tank 90 is raised and the tubes 3 areimmersed in the super-heated petrolatum up to the dashed line D forabout 30 seconds. The fourth dip tank is then lowered and the fourthcoating 78 of petrolatum is removed from the fourth portion 20d of theouter surface 20, as shown in FIG. 17.

(E) The pallet 64 is then automatically advanced and stopped over afifth dip tank 92 containing a volatile organic solvent such as toluene,trichloromethane or the like. The fifth tank 92 is then raised toimmerse the intermediate catheters 3 in the organic solvent up to dashedline D so as to remove any remaining petrolatum 66 on the fourth portion20d of the outer surface 20. The intermediate catheter tubes 3 now havethree bands 76, 77 and 78 of semi-solid petrolatum around the axialcircumference of each of the intermediate tubes 3, as shown in FIG. 17.

(F) The pallet 64 is then lowered, and the organic solvent is allowed toevaporate from the outer surface 20 for about 15 minutes. The pallet 64is then automatically advanced to a sixth dip tank 94 containing ahexamethyl disiloxane silicone rubber mixture which is effective tominimize any disruption of the integrity of the petrolatum coatings 76,77 and 78 remaining on the intermediate tubes 3. The preferred siliconerubber mixture is a 50-50 mixture of uncured silicone rubber inhexamethyl disiloxane. This mixture includes 12 parts by weight ofsilicone rubber No. 4850 (6 parts part A, 6 parts part B) from DowCorning; 12 parts by weight of silicone rubber No. 4720 (6 parts part A,6 parts part B) from Dow Corning; 64 parts by weight of hexamethyldisiloxane; and 2 parts by weight of Xylene. The sixth dip tank 94 isthen raised to immerse essentially the entire length of the intermediatetube 3 in the silicone mixture. This step is subsequently repeated 7times at 8-minute intervals to allow time for significant solventevaporation. A preferred thickness of the resulting overcoat layer 14 isabout 17.5 thousandths of an inch (plus or minus about 2.5 thousandthsof an inch). When the tank 94 is lowered for the last time, the overcoatlayer 14 is allowed to dry and the solvent is allowed to evaporate forabout 30 minutes, preferably about an hour.

(G) In a preferred embodiment of the present method, the pallet 24 isadvanced to yet another dip tank (not shown) similar to the others, butcontaining hot USP petrolatum, heated to about 170° F. (about 77# C.).

The tubes 3 are completely immersed in the hot petrolatum for 1 hr tocure the uncured silicone rubber and form the completed intermediatecatheters 4 shown in FIG. 18A, and the tank (not shown) is then lowered.

(H) The completed intermediate catheters 4 are then removed from thepallets and further cured in hot air at 220# F. (about 104# C.) forabout an hour and a half (1.5 hrs).

(I) After the completion of the heat cure, the intermediate catheters 4are allowed to cool and end pieces 80 are attached to the proximal ends61 of each of the intermediate catheters 4, and an eyelet 40 is createdto form the completed hand-actuated retention catheter 5. Alternatively,the intermediate catheters are soaked in hot mineral oil at 200# F. (93#C.) for 24 hours. The intermediate catheters 4 are then removed from theoil, cleaned and end pieces 80 are attached thereto, and an eyelet 40 iscreated to form the completed catheters 5.

(J) The completed Foley catheters 5 are finished by punching the fluidconduit access opening or eyelet 40 in the exterior surface 36 such thatit communicates with the fluid conduit lumen 8 in a location below ordistal to the expandable balloon section 32.

(K) If not previously soaked in mineral oil, the completed Foleycatheters 5 are then soaked for 24 hrs in a hot bath of mineral oil at200# F. (about 93# C.). The mineral oil will generally replace thepetrolatum 66 in the cavity 16 after this period of time, and willremain a fluid 18 at room temperature.

(L) The expandable balloon section 32 is then tested and stretched, andthe catheters 5 are packaged and then sterilized prior to shipment.

Referring now to FIGS. 20a, 20b and 20c, the present invention providesa method of making hand-actuated retention catheters 5 including thefollowing steps:

(A) Providing a tube having inner and outer surfaces, the inner surfacedefining an inner lumen;

(B) Cutting the tube to a desired length;

(C) Putting a tip on the distal end of the tube, thereby sealing off theinner lumen;

(D) Securing the tube to a moveable pallet.

These steps are followed by the following steps:

(A) Coating a first portion of the outer surface with a removable bondpreventing agent;

(B) Stripping the coating of removable bond preventing agent away fromthe second, third and fourth portions of the outer surface generallyadjacent to the first portion thereof;

(C) Coating the second, third and fourth portions of the outer surfacewith a further coating of removable bond preventing agent;

(D) Further coating the third portion of the outer surface with theremovable bond-preventing agent;

(E) Stripping the coating of bond-preventing agent from the fourthportion of the outer surface;

(F) Coating the outer surface and the remaining coatings of removablebond-preventing agent with an overcoat layer of a suitable film formingpolymeric bonding composition;

(G) Air drying the overcoat layer;

(H) Curing the overcoat layer to form the completed intermediatecatheter; and

(I) Soaking the intermediate catheter in a hot mineral oil bath (200#F.) for 24 hrs.

Following those steps, methods of the present invention include thefollowing steps:

(A) Punching a fluid conduit lumen access opening or eyelet in thedistal end of the intermediate catheter to communicate with the innerlumen;

(B) Securing an end piece to the proximal end of the intermediatecatheter to form a completed retention catheter;

(C) Testing the balloon portion of the resulting retention catheter;

(D) Packaging the resulting retention catheters; and

(E) Sterilizing the retention catheters.

The automated system that Applicants claim will permit completedcatheters 5 to be manufactured at the rate of about 1,600 catheters perhour. Because little handwork is involved, the catheters 5 produced willbe consistent, of very high quality, and more cost-effective thancomparable prior art catheters. The exterior surface 36 is believed tobe smoother than the exterior surface of hand-glued balloons.

The present invention also includes a method of making a silicone rubbercatheter 5 having an overcoat layer 14 enclosing a cavity 16 on an outersurface 20 of an inner tube 12, wherein the cavity 16 separates theovercoat layer 14 from the inner tube 12. The method includes providinga silicone rubber tube 12. Initially coating portions of an outersurface of the silicone rubber tube 12 with a bond preventing agent 66in a plurality of dipping steps, wherein the tube 12 is immersed intothe bond preventing agent 66 to a desired depth for a desired length oftime, and subsequently removed. The plurality of dipping steps areautomated in series by the mechanized catheter production line 81 whichincludes a computer control mechanism 83. The desired depth and/or thelength of time for each of the plurality of dipping steps is prescribedso that a residual coating of bond preventing agent remains on portionsof the silicone rubber tube 12 following the plurality of dipping steps.The residual coating has a variable thickness as a result of a variationbetween the number of dipping steps, the depth, and/or the length oftime of any two of the plurality of dipping steps. And, subsequentlycoating the silicone rubber tube 12 and the residual coating of bondpreventing agent 66 with a polymeric bonding composition containingsilicone rubber to form a shaped overcoat layer 14 wherein the shape ofthe overcoat layer 14 results in part from the variable thicknesses ofthe residual coating.

A step of initially coating preferably includes stripping the tube,wherein the tube is immersed in a stripping fluid to a desired depth fora desired length of time in order to remove at least a portion of thebond preventing agent from the outer surface 20 of the silicone rubbertube 12. Preferably, the overcoat layer 14 of the catheter 5 is shapedto include a bulbous balloon section 32 distal to a cylindrical sleevesection 34 interconnected therewith, wherein the thickness of theresidual coating of bond preventing agent 66, during the step ofsubsequently coating, is greater in a region proximate the bulbousballoon section 32 than it is in a region proximate the cylindricalsleeve section 34. In preferred embodiments, the overcoat layer 14 isshaped to include an enlarged cylindrical fluid reservoir section 30interconnected with and separated from the bulbous balloon section 32 bythe cylindrical sleeve section 34. The thickness of the residual coatingof bond preventing agent 66, during a step of subsequently coating, ispreferably lesser in a region proximate the cylindrical sleeve section34 than it is in regions proximate either the cylindrical fluidreservoir section 30 or the bulbous balloon section 32. Preferably, thepolymeric bonding composition is an uncured silicone rubber compositionand the step of subsequently coating is followed by a step of curing theuncured silicone rubber composition in the overcoat layer 14.

It is envisioned by the present Applicants that certain patients havinga urinary passageway 68 which narrows significantly proximate theurinary sphincter or the neck of the bladder may have difficulty usingthe present hand-actuated retention catheter 5. This is because thenarrowing of the urinary passageway 68 proximate the neck of the bladdermay force the catheter sleeve section 34 of the overcoat layer 14 upagainst the outer surface 20 of the tube 12 within the catheter sleeveportion 26 of the cavity 16 so that fluid is not able to pass out of theexpandable balloon portion 24 of the cavity 16 once that portion of thecavity 16 has been expanded with fluid 18 from the fluid reservoirportion 22. It will be appreciated that it may be difficult to removethe retention catheter 5 if this occurs, because the narrowness of theurinary passageway 68 will prevent the fluid 18 from leaving theexpandable balloon portion 24 of the cavity 16 even when the disc 50 isdeformed in a way which would otherwise allow fluid 18 to pass from theexpandable balloon portion 24 to the fluid reservoir portion 22.Although further confirmation that such idiosyncratic narrowings of theurinary passageway 68 of certain patients will cause this problem isstill being sought, the present Applicants envision several alternateembodiments of the present hand-actuated retention catheter 5 which willenable the Applicants to address this problem should it arise. It willbe appreciated that the Applicants have not as yet tested any of theseenvisioned solutions, and that the preferred embodiment which isultimately selected, has as yet to be fully designed, developed, testedand manufactured. It will be appreciated, however, that embodiments ofthe present hand-actuated retention catheter 5 which have additionalfeatures to address this problem include, but are not limited to, thefollowing alternate embodiments of the catheter.

Referring now also to FIGS. 22-24, an alternate hand-actuated retentioncatheter 5' is disclosed which is almost identical to the hand-actuatedretention catheter 5 shown in FIGS. 1-9, and will operate in virtuallythe same manner. The alternate embodiment, however, will have onesignificant difference. When making the alternate catheter 5', thealternate intermediate tube 12' will include a pair of grooves 13,15 inthe outer surface 20'. In the finished alternate catheter 5', thesegrooves 13,15 will extend only from a point within the catheter sleeveportion 26' distal to the location of the resilient disc 50', to a pointwithin the expandable balloon portion 24' of the cavity 16'. In thisway, the resilient disc 50' will function just as its counterpart disc50', functioned in the preferred catheter 5. In the alternate catheter5', if the urinary passageway 68 narrows so as to force the cathetersleeve section 34' of the overcoat layer 14' down upon the circumferenceof the outer surface 20' of the tube 12', fluid 18' will still be ableto flow from the expandable balloon portion 24' through the grooves13,15 within the otherwise closed-off catheter sleeve portion 26'. Thefluid 18 will flow into the fluid reservoir portion 22' under the forceof the resilient expandable balloon section 32' when the expandableballoon section 32' is in an expanded position and the resilient disc50' is deformed in a manner similar to that shown for the preferredcatheter 5 in FIG. 7. In preferred embodiments of the alternate catheter5', the alternate intermediate tube (not shown) used to make the tube12' is preferably injection-molded, preferably of a suitable siliconerubber material.

In yet other alternate embodiments (not shown), grooves (not shown)similar to grooves 13,15 of the alternate catheter 5' shown in FIGS.22-24, may extend all the way from the corresponding expandable balloonportion (not shown) to the corresponding fluid reservoir portion (notshown). In such an embodiment, the corresponding alternate tube (notshown) could also be injection molded. If the grooves (not shown) aredesigned to extend the entire length of yet another correspondingalternate tube (not shown), the corresponding alternate tube (not shown)could also be an extruded tube to which a molded tip is subsequentlyattached. In these two latter embodiments, neither of the correspondingalternate catheters (not shown) will need to have a resilientrestriction disc corresponding to that shown in FIGS. 1-9. In such acase, some type of resilient band (not shown), a clamping mechanism (notshown), or any other effective mechanism for compressing and retainingthe corresponding fluid reservoir section (not shown) in a compressedstate, generally similar to that shown for the preferred catheter 5 inFIGS. 5 and 9, will be necessary to prevent the respective correspondingexpandable balloon sections (not shown) from deflating once they havebeen expanded (such a device is shown in FIG. 27 for yet anotherembodiment). Since the groove or grooves (not shown) in the outersurface of the corresponding alternate tubes will extend all the wayfrom the corresponding alternate expandable balloon portion (not shown)to the corresponding alternate fluid reservoir portion (not shown) ofthe corresponding alternate cavities (not shown), the fluid will be ableto pass from one to the other even when the corresponding alternatecatheter sleeve section (not shown) is pressed against the circumferenceof the corresponding alternate outer surfaces of the correspondingalternate tubes in these respective embodiments.

Alternately, the grooves 13,15 shown in FIG. 24 is envisioned where afurther embodiment (not shown) similar to the alternate catheter 5',including grooves similar to the corresponding overcoat layer (notshown) is secured directly to the outer surface (not shown) of the tube(not shown), except where the outer surface recesses within therespective grooves.

Referring now also to FIGS. 25-29, yet further embodiments of thepresent invention could provide a corresponding alternate tube 5" whichhas a plurality of lumens 8", 27, one of which (27) communicates onlywith a first cavity 22", corresponding with the fluid reservoir portion22 of the preferred catheter 5, and a second cavity 24", correspondingto the expandable balloon portion 24 of the preferred catheter 5, viaaccess openings 23 and 25, respectively. In this alternate embodiment,there is no corresponding third cavity interconnecting the first andsecond cavities and corresponding to the catheter sleeve portion 26 ofthe preferred catheter 5. In this alternate embodiment, however, it isagain necessary to have a mechanism, such as the releasable bandmechanism 29 shown in FIG. 27, for compressing the first cavity andholding it in a compressed state such that the second cavity remains inan expanded state so as to provide a suitable retention mechanism forretaining this alternate catheter 5" within a urinary passageway (notshown). It will be appreciated that the second lumen 27 of the alternatecatheter 5" will allow fluid 18" to communicate at will between therespective first and second cavities 22",24", whether or not there is acorresponding third cavity interconnecting and communicating with eachof the respective first and second cavities.

In yet further alternate embodiments of the present catheter 5 which aresimilar to the latter alternate embodiment 5", a second lumen (notshown) may communicate between any of the respective first, second andthird corresponding alternate cavities. In a specific alternateembodiment envisioned by the Applicants, a second lumen 27 passingthrough the alternate tube 12" will interconnect first and secondalternate cavities 22" and 24", corresponding to the fluid reservoirportion 22 and the expandable balloon portion 24, respectively, of thepreferred catheter 5, and there will be no other means of communicationbetween the respective alternate cavities. In a further variation 5'" ofthis alternate catheter 5", shown in FIGS. 28 and 29, the firstreservoir 22'" will include a cylindrical narrowing distal thereto andextending toward, but not communicating with, the second cavity 24'".The access opening 23'" for the second lumen 27'" communicates with thefirst cavity 22'" within this narrowing, such that an alternateresilient disc 50'" similar to the disc 50 shown in FIG. 1 can be usedto restrict the flow of fluid 18'" from the narrowed extension portionof the first cavity 22'" into a larger portion thereof having greatercapacity to contain the fluid 18'". In this way, this alternateretention catheter 5'" can be provided with a resilient retention disc50'" which can be used in a similar way to the retention disc 50 shownin FIG. 1. However, a narrowing of the urinary passageway 68 proximatethe neck of the bladder which compresses the overcoat layer 14'" of thealternate catheter 5'" will not prevent fluid communication between therespective corresponding first and second cavities 22'" and 24'".

It is to be understood, however, that even,though numerouscharacteristics and advantages of the present invention have been setforth in the foregoing description, together with details of thestructure and function of the invention, the sequence or order of thespecific steps, or the actual compositions, solvents, temperatures,environmental conditions and the like employed for each step, it will beappreciated the disclosure is illustrative only, and that changes may bemade in detail, especially in matters of shape, size, arrangement ofparts or sequence or elements of events within the principles of theinvention to the full extent indicated by the broad general meaning ofthe terms in which the appended claims are expressed.

What is claimed is:
 1. A polymeric catheter having an overcoat layer onan outer surface of an inner polymeric structure, the overcoat layerhaving interior and exterior surfaces, a cavity interposed between thepolymeric structure and the overcoat layer, the overcoat layer beingjoined to the outer surface of the polymeric structure at ends of thecavity along the catheter, the cavity defined by a portion of the innersurface of the overcoat and a portion of the outer surface of thepolymeric structure, said cavity forming a fluid reservoir portion incommunication with a balloon portion, the fluid reservoir portion andthe balloon portion being interconnected by a catheter sleeve portion,said catheter made by the method comprising:(a) dipping a mandrel in apolymeric material to result in a polymeric structure on said mandrel;(b) coating different portions of an outer surface of said polymericstructure by dipping in a bond preventing agent in a plurality ofdipping steps to form a residual coating, wherein said residual coatingof said bond-preventing agent at said different portions has variablethicknesses; and (c) subsequently coating the polymeric structure withthe residual coating of said bond preventing agent with a polymericbonding composition by at least one dipping step in said polymericbonding composition to form a shaped overcoat layer, wherein the shapeof the overcoat layer results from the variable thicknesses of theresidual coating at said different portions.
 2. The polymeric catheterof claim 1, wherein said method additionally comprises:(e) subsequentlyreplacing the bond-preventing agent coated by the polymeric bondingcomposition with a fluid.
 3. The polymeric catheter of claim 1, whereinthe step of coating different portions of an outer surface of saidpolymeric structure by dipping in a bond-preventing agent in a pluralityof dipping steps to form a residual coating, includes stripping some ofthe bond-preventing agent from the polymeric structure by immersing thepolymeric structure in a stripping fluid following any of said pluralityof dipping steps to remove at least a portion of said bond-preventingagent from the outer surface of said polymeric structure.